Tendon-Inspired Piezoelectric Sensor for Biometric Application

In this article, a novel sensing structure is proposed to measure tensile loading. The sensing structure is motivated by the operating principle of the tendon. The fibroelastic characteristic of the tendon is implemented by combining sewing and elastic threads with a piezoelectric material, that is, a tendon-inspired piezoelectric sensor. The mechanical deformation of the tendon-inspired piezoelectric sensor was analyzed by applying tensile loading. Additionally, the electrical response according to the given tensile loading was measured and compared with the theoretical expectation. The experimental results found that the sensor outputs can be represented as a linear function along with elongation in a specific range. Furthermore, the motion-detecting capability of the sensor was demonstrated using body supports with seven tendon-inspired piezoelectric sensors. To show the feasibility of its application, a real-time motion detecting system using a virtual avatar was developed. The avatar showed good synchronization with the subject's upper-limb movements. This study provides insight into the sensing characteristics of the tendon-driven piezoelectric sensor and shows the potential for biometric applications.